Question

我有以下代码

public class dthvendas: System.Web.Services.WebService {

public class typVenda 
{
    //public string campanha;
    public string id;
    public string contact_moment;
    public string nome;
    // few more properties
}

[WebMethod][SoapDocumentMethod]

public typVenda getListaVendas(string dt_min, string dt_max)
{
    //venda vendas = new List<venda>();     
    typVenda objVenda = new typVenda();     

    SqlConnection con = new SqlConnection(@"Data Source=server;Initial Catalog=database;User ID=user;password=password");            
    //SqlCommand cmd = new SqlCommand("SELECT * FROM dbo where contact_moment >='" + dt_min + "' AND contact_moment <DATEADD(dd, 1, '" + dt_max + "')", con); 
    SqlCommand cmd = new SqlCommand("SELECT * FROM dbo.vcnosadesoes_getlistavendas", con); 

    con.Open();     
    SqlDataReader dr = cmd.ExecuteReader();
    if (dr.HasRows)
    {
        while (dr.Read())
        {

            //var objVenda = new typVenda();
            //objVenda.campanha = dr["id"].ToString();

            objVenda.id = dr["id"].ToString();
            objVenda.contact_moment = dr["contact_moment"].ToString();
            objVenda.nome = dr["nome"].ToString();
            objVenda.pacote = dr["pacote"].ToString();
            objVenda.telefone = dr["telefone"].ToString();
            objVenda.codigo_wc = dr["codigo_wc"].ToString();

            //vendas.Add(objVenda);
        }
        dr.Close();
    }
    con.Close();                        
    return objVenda;

    //return vendas.ToArray();                              
}

问题是只返回第一行而不是表中的所有行。什么问题可能是什么问题？

此外，当我返回它时说＆＃34;此XML文件似乎没有与之关联的任何样式信息。文档树如下所示。＆＃34;它应该有这样的标题：

<?xml version="1.0" encoding="UTF‐8" ?>

Answer 1

如果您在阅读器中有n个可用行，那么您可能会获得最后一行，因为创建的对象的属性在while (dr.Read())的每次迭代中都会被写入并最终将最新值返回给调用方法。您应该重新定义您的方法以返回List<typVenda>，从而使用在每次迭代中构造的对象填充列表。最后在迭代结束时返回列表。

更多建议为了改进代码：

在处理SqlConnection和SqlCommand时使用;因为您无需担心关闭连接和处理命令等使用将照顾这些事情
无需检查读者是否有行（if (dr.HasRows)）如果没有行，则while (dr.Read())将不会执行所附的语句。

现在考虑以下代码：

public List<typVenda> getListaVendas(string dt_min, string dt_max)
{
    List<typVenda> objVendaList = new List<typVenda>();

    using (SqlConnection con = new SqlConnection("connection String here"))
    {
        using (SqlCommand cmd = new SqlCommand("SELECT * FROM dbo.vcnosadesoes_getlistavendas", con))
        {
            con.Open();
            SqlDataReader dr = cmd.ExecuteReader();

            while (dr.Read())
            {

                var objVenda = new typVenda();

                // Assign the values to the properties here

                objVendaList.Add(objVenda);
            }
            dr.Close();
        }
    }
    return objVendaList;
}

Answer 2

public List<typVenda> getListaVendas(string dt_min, string dt_max)
{
    venda vendas = new List<typVenda>();     
    typVenda objVenda = new typVenda();     

    SqlConnection con = new SqlConnection(@"Data Source=server;Initial Catalog=database;User ID=user;password=password");            
    //SqlCommand cmd = new SqlCommand("SELECT * FROM dbo where contact_moment >='" + dt_min + "' AND contact_moment <DATEADD(dd, 1, '" + dt_max + "')", con); 
    SqlCommand cmd = new SqlCommand("SELECT * FROM dbo.vcnosadesoes_getlistavendas", con); 

    con.Open();     
    SqlDataReader dr = cmd.ExecuteReader();
    if (dr.HasRows)
    {
        while (dr.Read())
        {

            var objVenda = new typVenda();
            //objVenda.campanha = dr["id"].ToString();

            objVenda.id = dr["id"].ToString();
            objVenda.contact_moment = dr["contact_moment"].ToString();
            objVenda.nome = dr["nome"].ToString();
            objVenda.pacote = dr["pacote"].ToString();
            objVenda.telefone = dr["telefone"].ToString();
            objVenda.codigo_wc = dr["codigo_wc"].ToString();

            vendas.Add(objVenda);
        }
        dr.Close();
    }
    con.Close();                        

    return vendas;
}

WebService仅使用sql queryC＃返回第一行

2 个答案: